Explicitly declare parameter types as nullable

[imba28]

Starting with PHP 8.4, implicit nullability triggers a deprecation warning. See https://wiki.php.net/rfc/deprecate-implicitly-nullable-types. Excerpt from the logs

Deprecated: Codeception\Module\AMQP::pushToExchange(): Implicitly marking parameter $routing_key as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 112

Deprecated: Codeception\Module\AMQP::declareExchange(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 154

Deprecated: Codeception\Module\AMQP::declareExchange(): Implicitly marking parameter $ticket as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 154

Deprecated: Codeception\Module\AMQP::declareQueue(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 192

Deprecated: Codeception\Module\AMQP::declareQueue(): Implicitly marking parameter $ticket as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 192

Deprecated: Codeception\Module\AMQP::bindQueueToExchange(): Implicitly marking parameter $arguments as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 230

Deprecated: Codeception\Module\AMQP::bindQueueToExchange(): Implicitly marking parameter $ticket as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/codeception/module-amqp/src/Codeception/Module/AMQP.php on line 230